Japanese Encephalitis and Dengue are caused by the flaviviruses transmitted by the bite of mosquito. Both the infections are clinically important as they are more prevalent.

1. Clinical feature and diagnosis of
Japanese Encephalitis and Dengue
PRESENTER:- SACHIN CHAUDHARY
RESOURCE FACULTY:- DR. PRASHANT MANI TRIPATHI
MODERATOR:- DR. SAMYOG UPRETY

2. OBJECTIVES
Clinical features of Japanese Encephalitis
Diagnosis of Japanese Encephalitis
Clinical features of Dengue
Diagnosis of Dengue

3. Japanese Encephalitis

4. Clinical feature of Japanese
Encephalitis
Incubation period ranges between 5 and 15 days
1. Most of the infections occurs in childhood
2. Adult infections are less frequent
3. Mostly the disease is asymptomatic or mildly
symptomatic

5. Clinical Features
In symptomatic patients the disease
manifests in three phases:
1. Acute prodromal phase: before CNS entry by the
virus - fever, G.I. disturbances, headache, malaise etc
2. Encephalitic phase: After CNS entry by the virus-
rapid onset of high fever, neck stiffness, seizures,
spastic paralysis and death
3. Recovery phase: complete or partial recovery with
neurological deficits, cranial nerve palsies occurs

6. Prodromal Stage
It is characterised by
• Fever
• Rigors
• Headache
• Nausea & Vomiting
The Prodromal stage usually
lasts for 1 to 6 days. It can
be as short as less than 24
hours or as long as 14 days .

7. An Acute Encephalitic Stage:
Begins by the third to fifth day. The symptoms
include:
• Convulsions
• Altered sensorium, unconsciousness, coma
• Mask like face
• Stiff Neck
• Muscular Rigidity
• Tremors in fingers, tongue, eyelids and eyes.
• Abnormal movements of limbs
• Speech impairment

8. Late Stage
Characterized by the persistence of signs of
CNS injury such as,
• Mental impairment.
• Increased deep Tendon reflexes
• Paresis either of the upper or lower motor
neuron type.
• speech impairment
• Epilepsy, Abnormal movements, Behaviour
abnormalities.

10. Lab diagnosis
 Specimen: serum ,plasma ,CSF
 Antigen detection: Immunoflourescence
 Antibody detection:IgM capture ELISA
 Reverse transcriptase polymerase chain reaction
 Nucleic acid amplification test

11. Biochemical test
(CSF analysis)
 Protein content is elevated
 Glucose content may be normal
 CSF usually contain excess of lymphocytes but
polymorphonuclear cells may predominant in early
stage

12. Radiology
 Imaging by CT scan show low density lesions in
temporal lobe
 MRI is more sensitive in detecting early abnormalities

13. Isolation of virus
 It can be preformed ,but it is slow and
technically difficult ,and is often negative
because the virus has cleared by the
time the patients present to the hospital

14. Dengue

15. Clinical Features of Dengue
fever
 Fever
 Pain: Headache, retro-orbital
pain, joint pain, myalgia,
arthralgia (Breakbone fever)
 Rash(3-5 days)
 Enlarged lymph nodes
 Bleeding manifestations in
some

16. Fever
Fever is usually biphasic, temperature subsiding on
about the 3rd day and rising again about 5-6 day after
onset (saddleback form) usually last for 7-8 days.

17. Rash
1. Initial flushing faint macular
rash in first 1–2 days.
2. Maculopapular, scarlet morbilliform blanching
rash from days 3–5
on trunk, spreading centrifugally and sparing palms
and soles, onset often
with fever defervescence. May desquamate on
resolution or give rise to
petechiae on extensor surfaces

18. Clinical Criteria of Dengue
Dengue is defined by fever as reported by the patient or healthcare
provider and the presence of one or more of the following signs and
symptoms:
 Nausea/vomiting
 Rash
 Aches and pains (e.g., headache, retro-orbital pain, joint pain,
myalgia, arthralgia)
 Tourniquet test positive
 Leukopenia (a total white blood cell count of <5,000/mm3), or
 Any warning sign for severe dengue

19. Warning sign for severe
dengue:
 Abdominal pain or tenderness
 Persistent vomiting
 Extravascular fluid accumulation (e.g., pleural or
pericardial effusion, ascites)
 Mucosal bleeding at any site
 Liver enlargement >2 centimeters
 Increasing hematocrit concurrent with rapid decrease in
platelet count

20. Dengue Haemorrhagic Fever
Four cardinal feature of DHF (WHO)
• Increased vascular permeability (plasma leakage
syndrome) – evidence by hemoconcentration ≥20%^
in hematocrit, pleural effusion, or ascites
• Marked thrombocytopenia (<100,000/mm3)
• Fever lasting 2 to 7 days
• A hemorrhagic tendency (as demonstrated by
tourniquet or spontaneous bleeding : >20 petechiae in
one square inch)

21. Tourniquet test
 Inflate the cuff to a
point midway
between systolic
and diastolic
pressure for
5minutes.
 Positive test: 20 or
more petechiae
per sq. inch (6.25
sq cm)

22. Dengue Shock Syndrome
Criteria for DHF with shock manifested by:-
 Sudden deterioration
 Fall in temperature
 Signs of circulatory failure
 Metabolic acidosis
 Internal organ bleeding
 Electrolyte imbalance

23. Other uncommon symptoms
 Liver failure
 CNS dysfunction – encephalopathy, seizure, acute pure
motor weakness
 Acute abdomen pain

24. WHO Grading of DHF
This is especially useful in epidemics.
 Grade I: No shock only +ve tourniquet
 Grade II: No shock, spontaneous bleeding
 Grade III: Shock
 Grade IV: Profound shock

25. Laboratory diagnosis
Sample Collection:
 Early stages of the disease:
After the onset of illness, virus can be
detected in blood (serum, plasma)
or tissues.
 At the end of acute phase of infection:
Serology is the method of choice.

26. Serological Test
Serological tests are the mainstay in the diagnosis of viral
infections.
 Detection of Viral Antigen: Dengue NS1
Antigen detection
 Detection of Anti-dengue antibodies
 IgM/IgG ELISA: IgM detection is useful for the diagnosis
of primary Dengue infection and in distinguishing dengue
from other flavivirus infections.
 Hemagglutination Inhibition Test
 Rapid diagnostic kits

27. Virological and serological markers
in dengue infection

28. Isolation of Virus
Virus isolation in cell culture is difficult &
not the commonly used method in
diagnostic laboratories
Virus may be recovered from serum, plasma
and peripheral blood mononuclear cells.
Inoculation of a mosquito cell line with
patient serum, coupled with nucleic acid
assays to identify the recovered virus is
commonly used approach.

29. Isolation of virus -FAT

30. References
 Davidson's Principles and Practice of Medicine 23rd
Edition
 Harrison's Principles of Internal Medicine, 20th Edition
 https://wwwn.cdc.gov/nndss/conditions/dengue-virus-
infections